Bushing for carburetor plate linkage

ABSTRACT

In a carburetor induction throat, a plate carries a bracket with two parallel ears having coaxial circular openings therethrough. A bushing inserted through the circular openings has sectorshaped stops at one end for engagement with the plate to prevent rotation of the bushing and for engagement with an ear to prevent withdrawal of the bushing in one direction. The bushing further includes one or more deformable projections for engagement with an ear to prevent withdrawal of the bushing in the other direction and one or more deformable fingers at the other end tapering inward to facilitate bushing insertion. A link member includes a pin for insertion in the bushing having a circumferential groove at its free end to directly engage or hold a clip to engage the deformable fingers at the other end of the bushing in order to prevent withdrawal of the pin from the bushing.

[ Nov. 11, 1975 United States Patent [1 1 Judd 1 BUSHING FOR CARBURETORPLATE LINKAGE [75] Inventor: Richard K. Judd, Rochester, NY.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

[221 Filed: Nov. 1, 1974 [21] Appl. No: 519,835

[521 US. Cl 261/50 A; 403/161; 403/243 [51] Int. Cl. F02M 7/22 [58]Field of Search .v 261/50 A; 403/161, 162, 403/163, 243

[56] References Cited UNITED STATES PATENTS 2.041336 5/1936 Hall t t t w1 403/4162 $164,054 1/1965 Bieseckcrm. 403/163 3.356.426 12/1967 Fadow403/161 3.432.,152 3/1969 Sweeney 261/50 A 3.851.021 11/1974 Moulds261/50 A Primary Etutrtiner-Tim R Miles Attorney. Agent, or Ft'rntRobertM. Sigler 5 7 ABSTRACT In a carburetor induction throat, a plate carriesa bracket with two parallel ears having coaxial circular openingstherethrough. A bushing inserted through the circular openings hassector-shaped stops at one end for engagement with the plate to preventrotation of the bushing and for engagement with an ear to preventwithdrawal of the bushing in one direction. The bushing further includesone or more deformable projections for engagement with an ear to preventwithdrawal of the bushing in the other direction and one or moredeformable fingers at the other end tapering inward to facilitatebushing insertion. A link member includes a pin for insertion in thebushing having a circumferential groove at its free end to directlyengage or hold a clip to engage the defomiable fingers at the other endof the bushing in order to prevent withdrawal of the pin from thebushing.

2 Claims, 5 Drawing Figures U.S. Patent Nov. 11, 1975 BUSHING FORCARBURETOR PLATE LINKAGE SUMMARY OF THE INVENTION This inventioncomprises a bushing for use in a carburetor linkage mechanism such asthat used to coordinate movement between an air valve in an inductionthroat and a fuel metering valve.

In an air valve carburetor, a metering valve allows the flow of fuelinto the induction throat in proportion to the flow of air through thethroat as determined by an air valve. The proportional movement of theair and fuel metering valves is accomplished by a linkage mechanismconnecting them, the mechanism including a link which must be attachedto the air valve for movement therewith but remain free to rotate withrespect thereto. This invention is directed to a bushing for joining alink to an air valve, which bushing is self-locking, dependable,inexpensive and easy to assemble.

The mechanism includes a bracket fixed to the air valve and having apair of ears with coaxially circular openings and a pin on the end ofthe link for insertion through the openings. The bushing, surroundingthe pin in the bracket, has a number of tabs and fingers which preventits being withdrawn from the bracket once inserted and prevent the pinfrom being withdrawn from the bushing once inserted. Further details andadvantages of this invention will be apparent from the drawings and thefollowing description of the preferred embodiment.

SUMMARY OF THE DRAWINGS FIG. I shows a carburetor having a linkagemechanism with a bushing embodying this invention.

FIG. 2 shows a view along line 2-2 in FIG. 1.

FIG. 3 is a cutaway view along line 3-3 in FIG. 2.

FIG. 4 is a view along line 4-4 in FIG. 2.

FIG. 5 is a cutaway view along line 5-5 in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, acarburetor has an induction throat 11 including an air inlet 12 and amixture outlet 14 which discharges to an engine, not shown. A throttle15 is disposed in mixture outlet 14 in the usual manner.

An air valve 16 is disposed in air inlet 12 on an air valve shaft 18. Aspring 19 is hooked over the downstream edge 20 of air valve 16 orotherwise attached thereto and extends to a bracket 22 to bias air valve16 to the position shown.

A tang 23 reaches upwardly from air valve 16 and is connected by a link24 to a diaphragm 26. A chamber 27, fonned between the right side ofdiaphragm 26 and a cover member 28, is connected by a tube 30 to aregion 31 of induction throat ll defined between air valve 16 andthrottle valve 15.

A chamber 32, defined between the left side of diaphragm 26 and a covermember 34, is subjected to substantially atmospheric pressure throughopenings such as 35 and 36.

In operation, chamber 27 is subjected to the subatmospheric pressurecreated in region 31 as throttle 15 is opened, and diaphragm 26 actsthrough link 24 to pull air valve 16 to an open position. Spring 19 iseffective to balance the opening force of diaphragm 26, thereby creatinga substantially constant subatmospheric pressure in region 31. By thusestablishing a generally constant pressure across air valve 16, the areaabout air valve 16, and thus the rotational position of air valve 16, isdetermined by and is a measure of the rate of air flow through inductionthroat ll.

Carburetor 10 includes a fuel bowl 38 with a floatoperated valveassembly 39 to admit fuel thereto in the usual manner. A fuel passage 40has a lower end 42 disposed to receive fuel from a well 43 formed in thebottom of fuel bowl 38. The upper end 44 of fuel passage 40 has anopening 46 through which fuel is discharged into region 31 of inductionthroat 11. It will be appreciated, therefore, that the fuel in fuel bowl38 is subjected to a substantially constant metering head from thesubstantially atmospheric pressure in the upper portion of the fuel bowlto the generally constant pressure in region 31. A metering rod 47 isdisposed in fuel passage 40; and a metering jet or orifice 48 isdisposed in fuel passage 40 around the tip 50 of metering rod 47.Metering rod 47 has flat tapered surfaces 51 on opposite sides which,upon reciprocation of metering rod 47 in jet 48, vary the area availablefor fuel flow through jet 48.

Coordination of the metering rod 47 with air valve 16 is accomplished bya linkage mechanism including a hanger 52, the lower end of which has ahook 54 received in a recess 55 formed in metering rod 47. Hanger 52extends upward through an opening 56 in the cover 58 of fuel bowl 38 andis pivotably attached to a lever 59. Opening 56 is closed by a slider 60which shifts horizontally during movement of hanger 52.

One end 62 of lever 59 is pivoted about a pin 63 attached to a tang 64fixed to fuel bowl cover 58. The other end 66 of lever 59 is pivotablyattached to one end 67 of a link 68, the other end 70 of which ispivotably attached, in a manner to be described below, to a bracket 71mounted on air valve 16.

In operation, as air valve 16 opens via clockwise rotation link 68rotates lever 59 in a clockwise direction. Lever 59 then lifts hanger 52to move metering rod 47 generally upward and rightward in fuel passage40. Thus as air valve 16 is opened to increase the area available forair flow through air inlet 12, metering rod 47 is shifted to increasethe area available for fuel flow through metering orifice 48. By thismeans, a substantially constant air-fuel ratio may be maintained, theprecise proportion being controlled by the geometry of tapered surfaces57 and of the linkage between air valve 16 and metering rod 47.

Referring to FIGS. 2 through 5, the means by which link 68 is attachedto bracket 71 will be described in detail. Bracket 71 is shown to be agenerally U-shaped bracket having a flat horizontal portion 72 forattachment by welding or other means to air valve 16 and a pair ofparallel ears 73 projecting outward from opposite ends of horizontalportion 72 perpendicularly to air valve 16. Each ear 73 has a circularopening 74 therethrough, circular openings 74 being coaxial with eachother on an axis which, in this embodiment, is parallel with the axis ofair valve shaft 18.

Link 68, in this embodiment, is a fiat stamped piece of metal which canbe chosen from similar pieces of different length to set the initialair-fuel ratio of carburetor 10. Link 68 is provided, at end 70, with agenerally cylindrical pin 76 projecting perpendicularly outwardtherefrom. Pin 76 is provided, near its free end 77, with a peripheralgroove 78.

A bushing 80 is inserted through circular openings 74. Bushing 80 isstamped and formed out of sheet stock into a generally cylindricalsleeve 81 extending through circular openings 74 with a number offingers and stops projecting therefrom. At one end 82 of sleeve 81, oneor more sector-shaped stops 83 project radially outward perpendicularlyto the axis of sleeve 81. When viewed along the axis of sleeve 81, as inFIG. 5, these stops 83 are seen to be formed in the shape of sectors ofan annular ring. The outer radius of the annular ring is somewhatgreater than the distance between the axis of sleeve 81 or openings 74and air valve 16. A gap is provided between adjacent ends 84 of twoadjacent stops 83, or of the one stop 83 if there is only one; and thegap is of such size that one or the other of ends 84 engage air valve 16upon any attempted rotation of bushing 80 to prevent such rotation.Stops 83 also engage the adjacent car 73 to prevent withdrawal of thebushing from bracket 71 in one direction by being pushed completelythrough and serve as a washer between that adjacent ear 73 and link 68.

A pair of projections are punched out of the sleeve 81 so that theyextend toward stops 83 and are bent slightly radially outward.Projections 86 begin near the center of sleeve 81 and extend to a pointnear stops 83 and are deformable inward upon insertion of bushing 80through openings 74 but spring outward on the far side of the ear 73from stops 83 to prevent removal of the bushing in the other direction.Projections 86 can be formed in many other ways with different shapes ordesigns, as long as they are deformable to allow insertion through theopenings 74 but engage car 73 to hinder withdrawal of bushing 80.

From the other end 87 of bushing 80, a number of fingers 88, three inthis embodiment, extend axially and are bent somewhat radially inward tofacilitate insertion of bushing 80 through openings 74. The separationof end 87 into fingers 88 makes it easier to manufacture bushing 80 withthe desired taper in end 87.

To prevent the withdrawal of pin 76 from bushing 80, the fingers 88 caneither drop into groove 78 upon insertion or engage a standard C-clipinserted in a narrower groover 78 after pin 76 is inserted throughbushing 80. It is unimportant to this invention which method is used, aslongas pin 78 is provided with some means to engage fingers 88 andprevent withdrawal of pin 78 from bushing 80.

It can be seen from the preceding description that the bushing and pinmechanism is easy to assemble: pin 76 is simply inserted in bushing 80and bushing 80 in bracket 71, with either insertion first, followed bythe addition of a C-clip in groove 78, if desired. After assembly, innormal operation, pin 76 cannot be withdrawn from bushing 80; andbushing 80 cannot be withdrawn from openings 74 in bracket 71. Ofcourse, if some portion of the linkage needs repair or replacement, amechanic can remove the pin from the bushing or the bushing from thebracket by manually deforming the appropriate retaining projections orfingers.

The embodiments described above are preferred embodiments only; andequivalent embodiments, some of which have already been described, willoccur to those skilled in the art. Therefore the invention should belimited only by the claims which follow.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A carburetor comprising, in combination: a housing defining aninduction throat; a plate disposed rotatably in the induction throat; abracket disposed on the plate, the bracket including a pair ofprojecting ears, each ear having a circular opening therethrough, thecircular openings being coaxial; a plate-following link having acylindrical pin projecting therefrom through the circular openings; 21bushing including a generally cylindrical sleeve extending through thecircular openings around the pin, one or more stops at the end of thesleeve adjacent the link, the stops being engageable with the plate toprevent rotation of the bushing with respect thereto and furtherengageable with the ear adjacent the link to prevent withdrawal of thebushing from the circular openings in one direction, the bushing furtherincluding one or more projecting members being deformable to allowinsertion of the bushing through the openings but engageable with theear adjacent the link to prevent withdrawal of the bushing from the earsin the other direction, the end of the bushing opposite the link beingtapered to assist insertion of the bushing through the openings; andmeans provided for the pin near its end opposite the link for engagingthe tapered end of the bushing to prevent the withdrawal of the pin fromthe bushing.

2. A carburetor comprising, in combination: a housing defining aninduction throat; a plate disposed rotatably in the induction throat; abracket disposed on the plate, the bracket including a pair ofprojecting ears, each ear having a circular opening therethrough, thecircular openings being coaxial; a plate-following link having acylindrical pin projecting therefrom through the circular openings; abushing including a generally cylindrical sleeve extending through thecircular openings around the pin, one or more sector-shaped stopsradiating from the end of the sleeve adjacent the link, thesector-shaped stops having peripheral edges with a radius greater thanthe distance between the axis of the circular openings and the plate andbeing engageable with the plate to prevent rotation of the bushing withrespect thereto and with the ear adjacent the link to prevent withdrawalof the bushing from the circular openings in one direction, the bushingfurther including one or more projecting members being deformable topass through one of the circular openings upon insertibn of the bushingtherethrough but engageable with the ear adjacent the link to preventwithdrawal of the bushing from the circular openings in the otherdirection, the end of the bushing opposite the link including aplurality of inward tapering fingers to assist insertion of the bushingthrough the circular openings; and means provided for the pin near itsend opposite the link for engaging the tapered fingers to prevent thewithdrawal of the pin from the bushing.

1. A CARBURETOR COMPRISING, IN COMBINATION: A HOUSING DEFINING ANINDUCTION THROAT, A PLATE DISPOSED ROTATABLY IN THE INDUCTION THROAT, ABRACKET DISPOSED ON THE PLATE, THE BRACKET INCLUDING A PAIE OFPROJECTING EARS, EACH EAR HAVING A CIRCULAR OPENING THERETHROUGH, THECIRCULAR OPENINGS BEING COAXIAL, A PLATE-FOLLOWING LINK HAVVING ACYLINDRICAL PIN PROJECTINF THEREFROM THROUGH THE CIRCULAR OPENINGS, ABUSHING INCLUDING A GENEALLY CYLINDRICAL SLEEVE EXTENDING THROUGH THECIRCULAR OPENINGS AROUND THE PIN, ONE OR MORE STOPS ST THE END OF THESLEEVE ADJACENT THE LINK, THE STOPS BEING ENGAGEABLE WITH THE PLATE TOPREVENT ROTATION OF THE BUSHING WITH RESPECT THERETO AND FURTHERENGAGEABLE WITH THE EAR ADJACENT THE LINK TO PRE-
 2. A carburetorcomprising, in combination: a housing defining an induction throat; aplate disposed rotatably in the induction throat; a bracket disposed onthe plate, the bracket including a pair of projecting ears, each earhaving a circular opening therethrough, the circular openings beingcoaxial; a plate-following link having a cylindrical pin projectingtherefrom through the circular openings; a bushing including a generallycylindrical sleeve extending through the circular openings around thepin, one or more sector-shaped stops radiating from the end of thesleeve adjacent the link, the sector-shaped stops having peripheraledges with a radius greater than the distance between the axis of thecircular openings and the plate and being engageable with the plate toprevent rotation of the bushing with respect thereto and with the earadjacent the link to prevent withdrawal of the bushing from the circularopenings in one direction, the bushing further including one or moreprojecting members being deformable to pass through one of the circularopenings upon insertion of the bushing therethrough but engageable withthe ear adjacent the link to prevent withdrawal of the bushing from thecircular openings in the other direction, the end of the bushingopposite the link including a plurality of inward tapering fingers toassist insertion of the bushing through the circular openings; and meansprovided for the pin near its end opposite the link for engaging thetapered fingers to prevent the withdrawal of the pin from the bushing.